--- title: Diesel Smog Check Rules in Washoe County | Xpress Smog url: https://xpresssmogcenter.com/smog-check/diesel-smog-check/ business: Xpress Smog Check Center (Located inside Xpress Oil & Lube Center) locations: Reno Northwest: 6100 Mae Anne Ave, Reno, NV 89523, (775) 787-1000, Mon-Fri 8 am-5 pm, Sat 8 am-4 pm, Sun closed; Reno South: 4993 Longley Ln, Reno, NV 89502, (775) 828-6996, Mon-Fri 8 am-5 pm, Sat 8 am-3 pm, Sun closed type: Nevada smog check (vehicle emissions inspection), drive in, no appointment --- Located inside Xpress Oil & Lube Center - Smog check at two Reno locations - Oil change in the same visit - No appointment needed [Xpress Oil & Lube](https://xpressoilandlube.com/) - [Home](https://xpresssmogcenter.com/) - [Smog checks](https://xpresssmogcenter.com/smog-check/) - Diesel smog check rules # Diesel smog check rules In Washoe County a diesel needs a yearly smog check when its manufacturer's GVWR is 14,000 pounds or less, it is model year 1968 or newer, and it is past its first three registrations. Light-duty diesels get a dynamometer test, an opacity test and a visual inspection; call the service center before you bring a diesel. 4.7 stars from 550 Google reviews of the two Reno Xpress Oil & Lube Centers Diesel pickups are everywhere in northern Nevada, and the DMV treats them differently from gas vehicles in two ways: weight decides whether they test at all, and the test itself is more involved. Here are the rules from the DMV's diesel page. ## At a glance - Tested: diesels with a manufacturer's GVWR of 14,000 pounds or less, based in urban Washoe or Clark (Nevada DMV). - New diesels test from their fourth registration. - Light-duty diesel test = dynamometer + opacity + visual inspection of emission components. - Over 14,000 pounds: no annual test, but statewide roadside enforcement. ## The weight line For diesels, the DMV's test requirement turns on the manufacturer's gross vehicle weight rating. A diesel with a GVWR of 14,000 pounds or less, based in the urban areas of Washoe or Clark county and 1968 or newer, needs the annual test. Above that, it does not. The DMV adds a detail that trips people up: the manufacturer's weight rating decides, and it may differ from the declared weight you use for registration fees. Your renewal notice says whether a smog check is required. Most full-size diesel pickups, including the heavy-duty three-quarter and one-ton models, have GVWRs under 14,000 pounds and do test. ## How a light-duty diesel is tested The DMV describes the light-duty diesel inspection as three parts: a dynamometer test, where the truck runs under load on rollers; an opacity test, which measures how dense the exhaust is; and a visual inspection of the emission components. That equipment is not part of the OBD test gasoline cars get, so not every station tests diesels, and the DMV notes that some stations can only test two-wheel-drive vehicles or four-wheel drives running in two-wheel mode. Call the service center before you bring a diesel, and have your year, make, model and drive type ready. ## New diesel trucks New vehicles are exempt for their first three registrations, diesels included. The test starts at the fourth registration. ## Heavy diesels and the roadside rule Diesel vehicles over 14,000 pounds GVWR are not part of the annual smog check program, but the DMV's Heavy Duty Diesel Enforcement Team, made up of sworn peace officers, enforces air quality standards statewide. Officers conduct traffic stops for observed violations and periodic inspections at highway check sites and weigh stations, using the SAE J1667 snap acceleration test for exhaust opacity. The standards apply to every vehicle traveling in Nevada, including trucks registered in other states. ## Validity and renewal A diesel test is valid 90 days for most purposes and 180 days when the vehicle was bought from a Nevada dealer. Like any test, the result goes to the DMV electronically. If you are not sure whether your diesel needs a test, the DMV suggests contacting the Reno emission lab at (775) 684-3580. ### Sources - [dmv.nv.gov/emission_diesel.htm](https://dmv.nv.gov/emission_diesel.htm) (Nevada DMV Diesel Testing and Enforcement: criteria, test method, roadside enforcement; read 10/19/26) - [dmv.nv.gov/emission.htm](https://dmv.nv.gov/emission.htm) (Nevada DMV: diesel up to 14,000 lb GVWR, validity, exemptions; read 10/19/26) ### Your location: Reno South - Call [(775) 828-6996](tel:+17758286996) Mon-Fri 8 am-5 pm, Sat 8 am-3 pm, Sun closed - Address 4993 Longley Ln, Reno, NV 89502 [Directions](https://www.google.com/maps/dir/?api=1&destination=4993+Longley+Ln%2C+Reno%2C+NV+89502&destination_place_id=ChIJc5xNCcI_mYARXjHn3y79iJw) ### What a customer said Reno South I go here to get my person vehicle smogged and all of our fleet vehicles. The team here is great. They are attentive and quick with their work. I would highly recommend coming here if you're in Reno and need your car smogged. [All smog check reviews](https://xpresssmogcenter.com/reviews/) ### Related - [Diesel truck questions](https://xpresssmogcenter.com/faq/diesel-trucks/) - [Light-duty diesel testing: dynamometer and opacity](https://xpresssmogcenter.com/guides/diesel-opacity-and-dyno/) - [Motorhomes and heavier gas trucks](https://xpresssmogcenter.com/faq/motorhomes-and-heavy-trucks/) - [Smog checks for business fleets](https://xpresssmogcenter.com/smog-check/fleet-vehicles/) - [New vehicle exemption](https://xpresssmogcenter.com/smog-check/new-vehicle-exemption/) Located inside Xpress Oil & Lube Center Both smog check locations sit inside an Xpress Oil & Lube Center, the locally owned Reno drive-in that has served this town since 1983. Drive in, no appointment; get your oil changed in the same visit. [About us](https://xpresssmogcenter.com/about/) ## Related situations [### How the OBD smog test works The plug-in test for 1996 and newer cars and light trucks. Learn more](https://xpresssmogcenter.com/smog-check/obd-test/)[### 1968 to 1995 vehicles: the tailpipe test How older cars and heavy-duty trucks are tested. Learn more](https://xpresssmogcenter.com/smog-check/older-vehicles-tailpipe-test/)[### Hybrids and electric vehicles When a hybrid starts testing and why EVs never do. Learn more](https://xpresssmogcenter.com/smog-check/hybrid-and-electric-vehicles/)[### New vehicle exemption The first three registrations of a new car. Learn more](https://xpresssmogcenter.com/smog-check/new-vehicle-exemption/)[### Classic plates and other exemptions Classic Vehicle, Classic Rod, Old Timer and the rest of the exempt list. Learn more](https://xpresssmogcenter.com/smog-check/classic-and-exempt-vehicles/) ## Diesel smog check rules: questions Still have a question? Call either Reno location or just drive in; there is no appointment to make. ### My diesel pickup is a 2023 bought new. Does it test this year? Not until its fourth registration, under the DMV's new vehicle exemption. ### Where do I find my truck's GVWR? On the manufacturer's label, usually on the driver's door jamb. The DMV says the manufacturer's rating decides, not the declared weight on the registration. ### Is a diesel motorhome tested? A diesel at 14,000 pounds GVWR or less in a testing area is tested; heavier ones are not part of the annual program. Call before you bring a motorhome. ### Do out-of-state diesel trucks face Nevada rules? On the road, yes: the DMV says its roadside opacity standards apply to all vehicles traveling in Nevada. ## Two Reno locations, inside Xpress Oil & Lube Center [Reno Northwest smog check](https://xpresssmogcenter.com/locations/reno-mae-anne/)[Reno South smog check](https://xpresssmogcenter.com/locations/reno-longley/)